The disclosure relates to stabilizing jacks for recreational vehicles adapted to raise the recreational vehicle relative to its suspension to provide stability to the vehicle when parked. More specifically, the disclosure relates to stabilizing jacks having a locking feature to mitigate or preclude side-to-side sway of a vehicle supported or stabilized by the jack.
The present disclosure shows and describes embodiments of an illustrative stabilizing jack for vehicles having a pair of jack legs advanceable between retracted and extended or raised and lowered positions by a single drive assembly, wherein the drive assembly is mounted on a slide frame which is slidably mounted to a base frame. The base frame is securable to the frame of a vehicle, for example, a recreational vehicle, to stabilize the vehicle when parked.
When the legs are lowered on uneven ground, one leg will engage the ground before the other preventing that leg from further downward advancement but causing the drive assembly to drive the slide frame in an opposite direction while the other leg continues to advance downward until it engages the ground. Once both legs engage the ground, the balanced forces acting through the legs prevent the slide frame from sliding relative to the base frame such that the legs push downward on the ground with equal pressure, pushing upward on the slide frame and base frame and raising the vehicle.
In an embodiment, the drive assembly comprises a drive screw having adjacent left and right hand threaded sections with a screw follower or trunnion secured to each threaded section. Each leg is pivotally secured at a first end thereof to one of the screw followers. Struts or leg braces are pivotally connected at one end to each leg, medially thereof, and are pivotally connected at opposite ends to the base frame at the ends closest the respective leg.
When the screw followers are positioned centrally relative to the drive screw or in close proximity to the transition between the left and right hand threaded sections, the legs are positioned in a retracted position relative to the slide frame and base frame. When the screw is rotated in a first direction, the screw followers advance outward relative to the screw, causing the legs to pivot downward or toward an extended position. When the screw is rotated in an opposite direction, the screw followers advance inward relative to the screw, causing the legs to pivot upward or toward the retracted position.
As the screw is rotated in the first direction and one leg engages the ground before the other, the engagement of that leg against the ground resists outward advancement of the screw follower attached to the leg at its upper end thereof relative to the ground, such that the screw and the slide frame advance in the opposite direction relative to the ground until the other leg touches the ground. Once both legs touch the ground, the equal and opposite forces acting on the slide frame tend to raise it with respect to the base frame. As the slide frame is raised with respect to the base frame, pins located in the slide frame engage with slots located in the base frame to substantially preclude sliding of the slide frame with respect to the base frame. As the slide frame is further raised, it engages with the base frame, causing the base frame to push upward on the vehicle raising it relative to its suspension system.
The drive screw may be driven by a motor connected to the drive screw at one end thereof. The motor may be adapted to automatically shut off when the load thereon exceeds a selected amount, which may occur when the vehicle is raised sufficiently to stabilize the vehicle.